Organic and conventional fruits and vegetables contain equivalent counts of Gram-negative bacteria expressing resistance to antibacterial agents. - Related Documents




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392801.0000Organic and conventional fruits and vegetables contain equivalent counts of Gram-negative bacteria expressing resistance to antibacterial agents. Resistance to antibiotics is a major public health problem which might culminate in outbreaks caused by pathogenic bacteria untreatable by known antibiotics. Most of the genes conferring resistance are acquired horizontally from already resistant commensal or environmental bacteria. Food contamination by resistant bacteria might be a significant source of resistance genes for human bacteria but has never been precisely assessed, nor is it known whether organic products differ in this respect from conventionally produced products. We showed here, on a large year-long constructed sample set containing 399 products that, irrespective of their mode of production, raw fruits and vegetables are heavily contaminated by Gram-negative bacteria (GNB) resistant to multiple antibiotics. Most of these bacteria originate in the soil and environment. We focused on non-oxidative GNB resistant to third-generation cephalosporins, because of their potential impact on human health. Among them, species potentially pathogenic for immunocompetent hosts were rare. Of the products tested, 13% carried bacteria producing extended-spectrum beta-lactamases, all identified as Rahnella sp. which grouped into two phylotypes and all carrying the bla(RAHN) gene. Thus, both organic and conventional fruits and vegetables may constitute significant sources of resistant bacteria and of resistance genes.201019919536
340510.9999Practical implications of erythromycin resistance gene diversity on surveillance and monitoring of resistance. Use of antibiotics in human and animal medicine has applied selective pressure for the global dissemination of antibiotic-resistant bacteria. Therefore, it is of interest to develop strategies to mitigate the continued amplification and transmission of resistance genes in environmental reservoirs such as farms, hospitals and watersheds. However, the efficacy of mitigation strategies is difficult to evaluate because it is unclear which resistance genes are important to monitor, and which primers to use to detect those genes. Here, we evaluated the diversity of one type of macrolide antibiotic resistance gene (erm) in one type of environment (manure) to determine which primers would be most informative to use in a mitigation study of that environment. We analyzed all known erm genes and assessed the ability of previously published erm primers to detect the diversity. The results showed that all known erm resistance genes group into 66 clusters, and 25 of these clusters (40%) can be targeted with primers found in the literature. These primers can target 74%-85% of the erm gene diversity in the manures analyzed.201829346541
340620.9999Environmental and Pathogenic Carbapenem Resistant Bacteria Isolated from a Wastewater Treatment Plant Harbour Distinct Antibiotic Resistance Mechanisms. Wastewater treatment plants are important reservoirs and sources for the dissemination of antibiotic resistance into the environment. Here, two different groups of carbapenem resistant bacteria-the potentially environmental and the potentially pathogenic-were isolated from both the wastewater influent and discharged effluent of a full-scale wastewater treatment plant and characterized by whole genome sequencing and antibiotic susceptibility testing. Among the potentially environmental isolates, there was no detection of any acquired antibiotic resistance genes, which supports the idea that their resistance mechanisms are mainly intrinsic. On the contrary, the potentially pathogenic isolates presented a broad diversity of acquired antibiotic resistance genes towards different antibiotic classes, especially β-lactams, aminoglycosides, and fluoroquinolones. All these bacteria showed multiple β-lactamase-encoding genes, some with carbapenemase activity, such as the bla(KPC)-type genes found in the Enterobacteriaceae isolates. The antibiotic susceptibility testing assays performed on these isolates also revealed that all had a multi-resistance phenotype, which indicates that the acquired resistance is their major antibiotic resistance mechanism. In conclusion, the two bacterial groups have distinct resistance mechanisms, which suggest that the antibiotic resistance in the environment can be a more complex problematic than that generally assumed.202134572700
393030.9999Class 1 integron in staphylococci. As a major concern in public health, methicillin-resistant staphylococci (MRS) still remains one of the most prevalent pathogens that cause nosocomial infections throughout the world and has been recently labeled as a "super bug" in antibiotic resistance. Thus, surveillance and investigation on antibiotic resistance mechanisms involved in clinical MRS strains may raise urgent necessity and utmost significance. As a novel antibiotic resistance mechanism, class 1 integron has been identified as a primary source of antimicrobial resistance genes in Gram-negative organisms. However, most available studies on integrons had been limited within Gram-negative microbes, little is known for clinical Gram-positive bacteria. Based on series studies of systematic integrons investigation in hundreds of staphylococci strains during 2001-2006, this review concentrated on the latest development of class 1 integron in MRS isolates, including summary of prevalence and occurrence of class 1 integron, analysis of correlation between integron and antibiotic resistance, further demonstration of the role integrons play as antibiotic determinants, as well as origin and evolution of integron-associated gene cassettes during this study period.201121258866
394340.9999Quinolone resistance in the food chain. Antimicrobials are used in pet animals and in animal husbandry for prophylactic and therapeutic reasons and also as growth promoters, causing selective pressure on bacteria of animal origin. The impact of quinolones or quinolone-resistant bacteria on the management of human infections may be associated with three different scenarios. (i) Quinolone-resistant zoonotic bacterial pathogens are selected and food is contaminated during slaughter and/or preparation. (ii) Quinolone-resistant bacteria non-pathogenic to humans are selected in the animal. When the contaminated food is ingested, the bacteria may transfer resistance determinants to other bacteria in the human gut (commensal and potential pathogens). And (iii) quinolones remain in residues of food products, which may allow the selection of antibiotic-resistant bacteria after the food is consumed. In this review, we analyse the abovementioned aspects, emphasising the molecular basis of quinolone resistance in Escherichia coli, Salmonella spp. and Campylobacter spp.200818308515
392950.9999Genetic basis of antibiotic resistance in bovine mastitis and its possible implications for human and ecological health. Bovine mastitis is a mammary gland inflammation that can occur due to infectious pathogens, Staphylococcus aureus and Escherichia coli, which are, respectively, the most prevalent Gram-positive and Gram-negative bacteria associated with this disease. Currently, antibiotic treatment has become more complicated due to the presence of resistant pathogens. This review, therefore, aims to identify the most common resistance genes reported for these strains in the last four years. During the review, it was noted that bla(Z), bla(SHV,) bla(TEM), and bla(ampC) are the most reported genes for S. aureus and E. coli, associated with drug inactivation, mainly β-lactamases. They are characterized by generating bacterial resistance to β-lactam antibiotics, the most common treatment in animal and human bacterial treatments (penicillins and cephalosporins, among others). Genes associated with efflux systems were also present in the two strains and included norA, tetA, tetC, and tetK, which generate resistance to macrolide and tetracycline antibiotics. Additionally, the effects of spreading resistance between animals and humans through direct contact (such as consumption of contaminated milk) or indirect contact (through environmental contamination) has been deeply discussed, emphasizing the importance of having adequate sanitation and antibiotic control and administration protocols.202538916977
460860.9999Presence of Tetracycline and Sulfonamide Resistance Genes in Salmonella spp.: Literature Review. Tetracyclines and sulfonamides are broad-spectrum antibacterial agents which have been used to treat bacterial infections for over half a century. The widespread use of tetracyclines and sulfonamides led to the emergence of resistance in a diverse group of bacteria. This resistance can be studied by searching for resistance genes present in the bacteria responsible for different resistance mechanisms. Salmonella is one of the leading bacteria causing foodborne diseases worldwide, and its resistance to tetracyclines and sulfonamides has been widely reported. The literature review searched the Virtual Health Library for articles with specific data in the studied samples: the resistance genes found, the primers used in PCR, and the thermocycler conditions. The results revealed that Salmonella presented high rates of resistance to tetracycline and sulfonamide, and the most frequent samples used to isolate Salmonella were poultry and pork. The tetracycline resistance genes most frequently detected from Salmonella spp. were tetA followed by tetB. The gene sul1 followed by sul2 were the most frequently sulfonamide resistance genes present in Salmonella. These genes are associated with plasmids, transposons, or both, and are often conjugative, highlighting the transference potential of these genes to other bacteria, environments, animals, and humans.202134827252
340470.9999Association between antibiotic residues, antibiotic resistant bacteria and antibiotic resistance genes in anthropogenic wastewater - An evaluation of clinical influences. The high use of antibiotics in human and veterinary medicine has led to a wide spread of antibiotics and antimicrobial resistance into the environment. In recent years, various studies have shown that antibiotic residues, resistant bacteria and resistance genes, occur in aquatic environments and that clinical wastewater seems to be a hot spot for the environmental spread of antibiotic resistance. Here a representative statistical analysis of various sampling points is presented, containing different proportions of clinically influenced wastewater. The statistical analysis contains the calculation of the odds ratios for any combination of antibiotics with resistant bacteria or resistance genes, respectively. The results were screened for an increased probability of detecting resistant bacteria, or resistance genes, with the simultaneous presence of antibiotic residues. Positive associated sets were then compared, with regards to the detected median concentration, at the investigated sampling points. All results show that the sampling points with the highest proportion of clinical wastewater always form a distinct cluster concerning resistance. The results shown in this study lead to the assumption that ciprofloxacin is a good indicator of the presence of multidrug resistant P. aeruginosa and extended spectrum β-lactamase (ESBL)-producing Klebsiella spec., Enterobacter spec. and Citrobacter spec., as it positively relates with both parameters. Furthermore, a precise relationship between carbapenemase genes and meropenem, regarding the respective sampling sites, could be obtained. These results highlight the role of clinical wastewater for the dissemination and development of multidrug resistance.202031622887
340980.9999Antibiotic resistance genes in the bacteriophage DNA fraction of environmental samples. Antibiotic resistance is an increasing global problem resulting from the pressure of antibiotic usage, greater mobility of the population, and industrialization. Many antibiotic resistance genes are believed to have originated in microorganisms in the environment, and to have been transferred to other bacteria through mobile genetic elements. Among others, β-lactam antibiotics show clinical efficacy and low toxicity, and they are thus widely used as antimicrobials. Resistance to β-lactam antibiotics is conferred by β-lactamase genes and penicillin-binding proteins, which are chromosomal- or plasmid-encoded, although there is little information available on the contribution of other mobile genetic elements, such as phages. This study is focused on three genes that confer resistance to β-lactam antibiotics, namely two β-lactamase genes (blaTEM and blaCTX-M9) and one encoding a penicillin-binding protein (mecA) in bacteriophage DNA isolated from environmental water samples. The three genes were quantified in the DNA isolated from bacteriophages collected from 30 urban sewage and river water samples, using quantitative PCR amplification. All three genes were detected in the DNA of phages from all the samples tested, in some cases reaching 104 gene copies (GC) of blaTEM or 102 GC of blaCTX-M and mecA. These values are consistent with the amount of fecal pollution in the sample, except for mecA, which showed a higher number of copies in river water samples than in urban sewage. The bla genes from phage DNA were transferred by electroporation to sensitive host bacteria, which became resistant to ampicillin. blaTEM and blaCTX were detected in the DNA of the resistant clones after transfection. This study indicates that phages are reservoirs of resistance genes in the environment.201121390233
393790.9999Design of a system for monitoring antimicrobial resistance in pathogenic, zoonotic and indicator bacteria from food animals. DANMAP is a Danish programme for integrated monitoring of and research on antimicrobial resistance in bacteria from food animals, food and humans. The paper describes how bacteria from broilers, pigs, and cattle are collected, as well as the procedures for data handling and presentation of results. The bacteria from animals include certain pathogens, selected so that they are representative for submissions to Danish diagnostic laboratories, as well as zoonotic bacteria (Campylobacter, Salmonella and Yersinia) and indicator bacteria (E. coli, E. faecium and E. faecalis), from samples collected at abattoirs. The latter samples are selected so that they are representative of the respective animal populations. Therefore, the apparent prevalence of antimicrobial resistance in the populations may be calculated. The isolates are identified to species level and the results of susceptibility testing are stored as continuous variables. All isolates are maintained in a strain collection so that they are available for subsequent research projects. The data handling facilities makes it possible to present results as percent resistant isolates or as the apparent prevalence of resistance in the population, or alternatively as graphical distributions of mm inhibition zones or MIC values. Computer routines have been established that make it possible to detect specific phenotypic expressions of resistance that may be of particular interest.199910783720
9919100.9999An In Vitro Chicken Gut Model Demonstrates Transfer of a Multidrug Resistance Plasmid from Salmonella to Commensal Escherichia coli. The chicken gastrointestinal tract is richly populated by commensal bacteria that fulfill various beneficial roles for the host, including helping to resist colonization by pathogens. It can also facilitate the conjugative transfer of multidrug resistance (MDR) plasmids between commensal and pathogenic bacteria which is a significant public and animal health concern as it may affect our ability to treat bacterial infections. We used an in vitro chemostat system to approximate the chicken cecal microbiota, simulate colonization by an MDR Salmonella pathogen, and examine the dynamics of transfer of its MDR plasmid harboring several genes, including the extended-spectrum beta-lactamase bla(CTX-M1) We also evaluated the impact of cefotaxime administration on plasmid transfer and microbial diversity. Bacterial community profiles obtained by culture-independent methods showed that Salmonella inoculation resulted in no significant changes to bacterial community alpha diversity and beta diversity, whereas administration of cefotaxime caused significant alterations to both measures of diversity, which largely recovered. MDR plasmid transfer from Salmonella to commensal Escherichia coli was demonstrated by PCR and whole-genome sequencing of isolates purified from agar plates containing cefotaxime. Transfer occurred to seven E. coli sequence types at high rates, even in the absence of cefotaxime, with resistant strains isolated within 3 days. Our chemostat system provides a good representation of bacterial interactions, including antibiotic resistance transfer in vivo It can be used as an ethical and relatively inexpensive approach to model dissemination of antibiotic resistance within the gut of any animal or human and refine interventions that mitigate its spread before employing in vivo studies.IMPORTANCE The spread of antimicrobial resistance presents a grave threat to public health and animal health and is affecting our ability to respond to bacterial infections. Transfer of antimicrobial resistance via plasmid exchange is of particular concern as it enables unrelated bacteria to acquire resistance. The gastrointestinal tract is replete with bacteria and provides an environment for plasmid transfer between commensals and pathogens. Here we use the chicken gut microbiota as an exemplar to model the effects of bacterial infection, antibiotic administration, and plasmid transfer. We show that transfer of a multidrug-resistant plasmid from the zoonotic pathogen Salmonella to commensal Escherichia coli occurs at a high rate, even in the absence of antibiotic administration. Our work demonstrates that the in vitro gut model provides a powerful screening tool that can be used to assess and refine interventions that mitigate the spread of antibiotic resistance in the gut before undertaking animal studies.201728720731
3938110.9998Human health hazards associated with the administration of antimicrobials to slaughter animals. Part II. An assessment of the risks of resistant bacteria in pigs and pork. Risks for the consumer regarding the acquisition of resistant bacteria and/or resistance genes via the consumption of pork are discussed. In general, Salmonella spp. and Escherichia coli that originate from animals do not easily transfer their resistance genes to the resident intestinal flora of humans. The prevalence of resistant E. coli in humans seems more associated with being a vegetarian (odds ratio (OR) 1.89) than with the consumption of meat and meat products. Other risk factors are treatment with antimicrobials (OR 2-5), becoming hospitalized (OR 5.93), or working in a health setting (OR 4.38). In the Netherlands, annually an estimated 45,000 people (0-150,000) become a carrier of resistant E. coli and/or resistance genes that ori ginate from pigs, while an estimated 345,000 persons (175,000-600,000) become a carrier of resistant E. coli and/or resistance genes that originate from hospitals, e.g. other patients. Any problems with resistant Salmonella spp. that stem from pigs are, in fact, an integral part of the total problem of food-borne salmonellosis. Sometimes there are outbreaks of a specific multi-resistant clone of S. typhimurium that causes problems in both farm animals and humans. The probability that in the next 30 years there is no or maximally one outbreak of a specific clone that originates from pig herds is estimated at about 75%. Antimicrobials used as a growth promoter can have a measurable influence on the prevalence of resistant bacteria. The likely chain of events regarding avoparcin and the selection and dissemination of resistance against vancomycin in the enterococci gives the impression that the impact of the use of antimicrobials in animals on the prevalence of resistance in humans is largely determined by whether resistance genes are, or become, located on a self-transferable transposon. Furthermore, consumer health risks of antimicrobials used in slaughter pigs are mainly determined by the selection and dissemination of bacterial resistance and much less by the toxicological properties of any residues in pork. It is also concluded that most of the problems with resistant bacteria in humans are associated with the medical use of antimicrobials, and that the impact of particularly the veterinary use of antimicrobials is limited. However, the impact of antimicrobials used as a feed additive appears to be much greater than that of antimicrobials used for strictly veterinary purposes. The use of antimicrobials as a feed additive should therefore be seriously reconsidered.200111205995
4320120.9998The mobilome landscape of biocide-resistance in Brazilian ESKAPE isolates. The increasing frequency of antibiotic-resistant bacteria is a constant threat to global human health. Therefore, the pathogens of the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter spp.) are among the most relevant causes of hospital infections responsible for millions of deaths every year. However, little has been explored about the danger of microorganisms resistant to biocides such as antiseptics and disinfectants. Widely used in domestic, industrial, and hospital environments, these substances reach the environment and can cause selective pressure for resistance genes and induce cross-resistance to antibiotics, further aggravating the problem. Therefore, it is necessary to use innovative and efficient strategies to monitor the spread of genes related to resistance to biocides. Whole genome sequencing and bioinformatics analysis aiming to search for sequences encoding resistance mechanisms are essential to help monitor and combat these pathogens. Thus, this work describes the construction of a bioinformatics tool that integrates different databases to identify gene sequences that may confer some resistance advantage about biocides. Furthermore, the tool analyzed all the genomes of Brazilian ESKAPE isolates deposited at NCBI and found a series of different genes related to resistance to benzalkonium chloride, chlorhexidine, and triclosan, which were the focus of this work. As a result, the presence of resistance genes was identified in different types of biological samples, environments, and hosts. Regarding mobile genetic elements (MGEs), around 52% of isolates containing genes related to resistance to these compounds had their genes identified in plasmids, and 48.7% in prophages. These data show that resistance to biocides can be a silent, underestimated danger spreading across different environments and, therefore, requires greater attention.202439028534
6620130.9998The growing burden of antimicrobial resistance. Since the first usage of antimicrobials, the burden of resistance among bacteria has progressively increased and has accelerated within the last 10 years. Antibiotic resistance genes were present at very low levels prior to the introduction of antibiotics and it is largely the selective pressure of antibiotic use and the resulting exposure of bacteria, not only in humans but also in companion and food animals and the environment, which has caused the rise. The increasing mobility across the globe of people, food and animals is another factor. Examples of this are the international pandemic of different genotypes of CTX-M extended-spectrum beta-lactamases (particularly CTX-M-14 and -15) and the emergence of the carbapenemase KPC-1 in both the USA and Israel. This review details examples of both the emergence and dissemination through different genetic routes, both direct and indirect selective pressure, of significance resistance in Staphylococcus aureus, Enterococcus species, Enterobacteriaceae and Pseudomonas/Acinetobacter. The response made by society to reduce resistance involves surveillance, reduced usage, improved infection control and the introduction of new antimicrobial agents. Although efforts are being made in all these areas, there is an urgent need to increase the effectiveness of these interventions or some bacterial infections will become difficult if not impossible to treat reliably.200818684701
3934140.9998Prevalence of antimicrobial resistance genes and its association with restricted antimicrobial use in food-producing animals: a systematic review and meta-analysis. BACKGROUND: There is ongoing debate regarding potential associations between restrictions of antimicrobial use and prevalence of antimicrobial resistance (AMR) in bacteria. OBJECTIVES: To summarize the effects of interventions reducing antimicrobial use in food-producing animals on the prevalence of AMR genes (ARGs) in bacteria from animals and humans. METHODS: We published a full systematic review of restrictions of antimicrobials in food-producing animals and their associations with AMR in bacteria. Herein, we focus on studies reporting on the association between restricted antimicrobial use and prevalence of ARGs. We used multilevel mixed-effects models and a semi-quantitative approach based on forest plots to summarize findings from studies. RESULTS: A positive effect of intervention [reduction in prevalence or number of ARGs in group(s) with restricted antimicrobial use] was reported from 29 studies for at least one ARG. We detected significant associations between a ban on avoparcin and diminished presence of the vanA gene in samples from animals and humans, whereas for the mecA gene, studies agreed on a positive effect of intervention in samples only from animals. Comparisons involving mcr-1, blaCTX-M, aadA2, vat(E), sul2, dfrA5, dfrA13, tet(E) and tet(P) indicated a reduced prevalence of genes in intervention groups. Conversely, no effects were detected for β-lactamases other than blaCTX-M and the remaining tet genes. CONCLUSIONS: The available body of scientific evidence supported that restricted use of antimicrobials in food animals was associated with an either lower or equal presence of ARGs in bacteria, with effects dependent on ARG, host species and restricted drug.202133146719
3896150.9998Antimicrobial resistance genes in bacteria from animal-based foods. Antimicrobial resistance is a worldwide public health threat. Farm animals are important sources of bacteria containing antimicrobial resistance genes (ARGs). Although the use of antimicrobials in aquaculture and livestock has been reduced in several countries, these compounds are still routinely applied in animal production, and contribute to ARGs emergence and spread among bacteria. ARGs are transmitted to humans mainly through the consumption of products of animal origin (PAO). Bacteria can present intrinsic resistance, and once antimicrobials are administered, this resistance may be selected and multiply. The exchange of genetic material is another mechanism used by bacteria to acquire resistance. Some of the main ARGs found in bacteria present in PAO are the bla, mcr-1, cfr and tet genes, which are directly associated to antibiotic resistance in the human clinic.202032762867
4212160.9998Review on the occurrence of the mcr-1 gene causing colistin resistance in cow's milk and dairy products. Both livestock farmers and the clinic use significant amount of antibiotics worldwide, in many cases the same kind. Antibiotic resistance is not a new phenomenon, however, it is a matter of concern that resistance genes (mcr - Mobilized Colistin Resistance - genes) that render last-resort drugs (Colistin) ineffective, have already evolved. Nowadays, there is a significant consumption of milk and dairy products, which, if not treated properly, can contain bacteria (mainly Gram-negative bacteria). We collected articles and reviews in which Gram-negative bacteria carrying the mcr-1 gene have been detected in milk, dairy products, or cattle. Reports have shown that although the incidence is still low, unfortunately the gene has been detected in some dairy products on almost every continent. In the interest of our health, the use of colistin in livestock farming must be banned as soon as possible, and new treatments should be applied so that we can continue to have a chance in fighting multidrug-resistant bacteria in human medicine.202133898852
4179170.9998Epidemiology of Antimicrobial Resistance Genes in Streptococcus agalactiae Sequences from a Public Database in a One Health Perspective. Streptococcus agalactiae is a well-known pathogen in humans and food-producing animals. Therefore, this bacterium is a paradigmatic example of a pathogen to be controlled by a One Health approach. Indeed, the zoonotic and reverse-zoonotic potential of the bacteria, the prevalence of Group B Streptococci (GBS) diseases in both human and animal domains, and the threatening global situation on GBS antibiotic resistance make these bacteria an important target for control programs. An epidemiological analysis using a public database containing sequences of S. agalactiae from all over the world was conducted to evaluate the frequency and evolution of antibiotic resistance genes in those isolates. The database we considered (NCBI pathogen detection isolate browser-NPDIB) is maintained on a voluntary basis. Therefore, it does not follow strict epidemiological criteria. However, it may be considered representative of the bacterial population related to human diseases. The results showed that the number of reported sequences increased largely in the last four years, and about 50% are of European origin. The frequency data and the cluster analysis showed that the AMR genes increased in frequency in recent years and suggest the importance of verifying the application of prudent protocols for antimicrobials in areas with an increasing frequency of GBS infections both in human and veterinary medicine.202236140016
4845180.9998The changing epidemiology of resistance. Antibiotic resistance is now a linked global problem. Dispersion of successful clones of multidrug resistant (MDR) bacteria is common, often via the movement of people. Local evolution of MDR bacteria is also important under the pressure of excessive antibiotic use, with horizontal gene transfer providing the means by which genes such as bla(CTX-M) spread amongst different bacterial species and strains. Beta-lactamase production is a common resistance mechanism in Gram-negative bacteria, and the rapid dissemination of novel genes reflects their evolution under the selective pressure of antibiotic usage. Many Enterobacteriaceae now carry broad-spectrum beta-lactamases such as CTX-M, with particular genotypes associated with different geographical regions. The spread of these enzymes has compromised the clinical utility of a number of beta-lactam classes and with the spread of genes such as bla(KPC), carbapenems may be increasingly compromised in the future. High-level fluoroquinolone resistance (mainly caused by gyrA mutations) has also been shown to be associated with CTX-M and CMY-type enzymes, commonly due to co-carriage on conjugative plasmids of the gene for the aminoglycoside-inactivating enzyme AAC-6(1)-Ib-cr and qnr genes (which confer low-level resistance), allowing the easy selection of gyrA mutants in the host strain. Resistance in Gram-positive bacteria is also widely distributed and increasing, with the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) blurring the distinction between hospital and community strains. Antibiotic use and environmental factors all have a role in the emergence and spread of resistance. This article reviews some of the new mechanisms and recent trends in the global spread of MDR bacteria.200919675017
4843190.9998The Efficacy of Isolated Bacteriophages from Pig Farms against ESBL/AmpC-Producing Escherichia coli from Pig and Turkey Farms. Extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases are plasmid (but also chromosomally) encoded enzymes found in Enterobacteriaceae, determining resistance to a variety of important antibiotics including penicillins, cephalosporins, and monobactams. In recent decades, the prevalence of ESBL/AmpC-producing bacteria has increased rapidly across the world. Here, we evaluate the potential use of bacteriophages in terms of a reduction of antibiotic-resistant bacteria in healthy animals. The aim of our studies was to isolate bacteriophages capable of destroying ESBL/AmpC-producing Escherichia coli isolated from livestock habitats. The efficacy of isolated phages against ESBL/AmpC E. coli strains varies, but creation of a phage cocktail with broad activity spectrum is possible. This may indicate that the role of phages may not be limited to phage therapy, but bacterial viruses may also be applied against spread of bacteria with antibiotic resistance genes in the environment. We also addressed the hypothesis, that phages, effective for therapeutic purposes may be isolated from distant places and even from different environments other than the actual location of the targeted bacteria. This may be beneficial for practical purposes, as the construction of effective phage preparations does not require access to disease outbreaks.201728405193